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Best Fish Tank Filters for 2020

Keeping your aquarium free of dirt and grime is essential for the wellbeing of your pet fish. Not only can a build-up of dirt and ammonia be lethal for your fish, but it also means that the tank looks less than pleasant.

As you will read, however, buying a filter is not an easy process. You have to accommodate the size of the tank, the water capacity, how well your fish can swim, and how much room you have for the filter. The water also has to be cleaned both physically and chemically.

We’ve rounded down the selection out there into a top ten review, and have chosen a wide range of filters to suit all needs and price ranges.

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    Our Top Picks

    Image Product Details
    Fluval External Filter for Aquariums
    • Quiet
    • Simple to manage
    Check Price
    Interpet Internal Aquarium Power Filter Mini
    • For tropical or cold water tanks
    • Easy maintenance
    Check Price
    Fluval U Series Underwater Aquarium Filter
    • Quiet
    • Easy to open to maintain
    Check Price

    Top 10 Best Fish Tank Filters Reviewed

    1.
    Fluval External Filter for Aquariums

    Available in four different sizes, which can host tanks up to 130L, 220L, 330L and 500L, this external filter is fabulous if you can’t waste any space in your tank and want something which is incredibly quiet.

    It is efficient, drawing as little as 10 Watts of electrical energy for the smallest size. Constant pumping power and pressure means it lasts for longer than its closest rivals, and it is really simple to look after too. Easy-lift media baskets mean no mess, and aquastop valves allow you to disconnect the hose with ease.

    The bio-foam max pre-filter is dense, providing more surface area and a better chance of capturing even the smallest of particles. Rubber feet stabilisers give it a more solid base when standing on a surface.

    Features

    • Quiet
    • Simple to manage

    Specifications

    • Type: External
    • Filter Types: Triple Stage
    • Tank Size: 130-500L
    • Water Flow Rate: Varies

    2.
    Interpet Internal Aquarium Power Filter Mini

    Small tank filters don’t need as much power behind them, but they still need to do just as good a job.

    This model is a triple-stage option, so it will deal with all three filter types and still take up little space. You can change the flow rate and the direction, which will ensure it cleans every last bit of your water.

    The patented aqua valve is there to stop any waste materials escaping back into the water after collection, and a rocker switch allows you to adjust the ventilation. The easy-clean filter is also beneficial as it is easy to access, so you can keep on top of its care.

    With a maximum water flow rate of 200 litres every hour, it easily copes with refreshing an entire tank a few times every hour. It uses just 5W of power too, making it very energy efficient.

    We will say that if your tank is very tiny, it could be a little bit too powerful, especially if you have small fish in there as they may not be able to keep up with the current. Sticking to tanks around 20L or more may be best.

    Features

    • For tropical or cold water tanks
    • Easy maintenance

    Specifications

    • Type: Internal
    • Filter Types: Triple Stage
    • Tank Size: 5-40L
    • Water Flow Rate: 200 LPH

    3.
    Fluval U Series Underwater Aquarium Filter

    With top access for easy maintenance and three-stage filtration to keep all of the cleaning needs in one place, these are great underwater filter systems which create a superior water quality.

    The adjustable flow control allows you to fine-tune the power according to the size of the tank and the fish residing in it. It comes with the filters and bio max filter media, making it easy to get going but also to replace them as and when needed.

    Suction cups keep the whole unit in place really well, and it can be removed without taking these off which helps with future placement. Choose from U1, U2, U3 and U4 models depending on the size of your tank, and all are nice and quiet.

    They can be used in freshwater, marine or reptile environments.

    Features

    • Quiet
    • Easy to open to maintain

    Specifications

    • Type: Internal
    • Filter Types: Triple
    • Tank Size: Up to 150L
    • Water Flow Rate: 250-1,000 LPH

    4.
    All Pond Solutions Ltd Aquarium Hang on Back External Filter

    Able to cope with massive tanks up to 250 litres thanks to its 500 litres per hour flow rate, this is a great filter for a big tank when you don’t want to have to take up internal space.

    The adjustable flow rate will allow you to use it on smaller tanks as well, and the adjustable width brackets mean it can hook onto widths of up to 15mm. A set of five media baskets mean that the water travels through several layers before being redispersed into the tank, ensuring it is crystal clear. It also means there is a perfect level of good bacteria dispersed.

    We love how you can choose between a spray bar or outlet nozzle for the part which replaces the water, meaning the flow can be as gentle as you need it to be. The pipework is also height adjustable.

    It can be used for saltwater as well as freshwater tanks as well, which will appeal to anyone struggling to find something suitable for their marine tank.

    Features

    • Very adjustable to suit tank
    • Good value

    Specifications

    • Type: Power
    • Filter Types: Triple
    • Tank Size: 250L
    • Water Flow Rate: 500 LPH

    5.
    Supa Under Gravel Aquarium Filter

    Suitable for tropical, marine or cold water aquariums, this easy to install filter has a surprisingly high filtration rate.

    It is available in four different sizes, depending on your tank size. You have a bit of freedom of where to place the airlift tube, and it offers protection against ‘digging-up’ by fish, so your gravel will remain in place for a more effective clean.

    The airlift tube is also easily cleaned, so you can keep it running at its best over time. Spare airlift tubes are also available, in case they need replacing or you need some extra power.

    Features

    • Eliminates filter wool layer

    Specifications

    • Type: Under gravel
    • Filter Types: Biological
    • Tank Size: Varies
    • Water Flow Rate: N/A

    6.
    Interpet Cartridge Filter CF Range

    A unique support cradle to make it easy to install, this is a great internal filter for anyone who wants something simple to manage.

    Suitable for cold water and tropical aquariums, you can choose from CF Mini, CF1, CF2, or CF3 depending on the size of your tank. All use 10.5W of power at the very most, making them efficient to run while still doing their job.

    The maximum flow rates are huge, all over four times as much as the water capacity, so it is no surprise that the water stays really clean. They use mechanical floss and carbon as filters, which trap fine waste and purifies water for chemical and mechanical help.

    We will mention that the holes at the base of the filter are quite large, so if you have mini fish, this is not ideal.

    Features

    • Sucker mounted for an easy fit
    • Slot-in disposable cartridge filters

    Specifications

    • Type: Internal
    • Filter Types: Mechanical
    • Chemical Tank Size: 12-160L
    • Water Flow Rate: 130-700 LPH

    7.
    Tetra Tetratec EasyCrystal 300 Aquarium Internal Filter

    A very easy filter to look after, all you need to do is replace the cartridge every four weeks and it will do all the hard work for you. No getting your hands wet or cleaning it all out.

    Double layered filter floss pads remove even the smallest of particles from the water, and filter foam and biofilter balls offer an extra-large surface area for the settlement of beneficial bacteria. Finally, the carbon removes any cloudy water or smells.

    It is a space-saving unit, so won’t be bulky and cumbersome within the tank. The filter is also quiet, so the only noise you will hear is the pump getting to work.

    There is an additional heater compartment if needed, with the heater bought separately. An EasyCrystal 250 or 600 are also available if you have a larger or smaller tank than the 300 accommodates.

    Features

    • Easy to care for
    • Intensive triple filter action

    Specifications

    • Type: Internal
    • Filter Types: Triple
    • Tank Size: 40-60L
    • Water Flow Rate: 250 LPH

    8.
    Penn Plax Smallworld Pump and Filter Kit

    Great for small aquariums, bowls and betta tanks, this filter will remove harmful gasses and discolouration from the water and is great for weaker swimmers.

    The air pump will stir up the water in the tank to ensure it is all removed and cleaned frequently. Disposable carbon and sponge filter cartridges mean there is little upkeep, and it will also trap bits of mechanical waste.

    An adjustable bubble flow can suit betta fish who like the water to be quite still, or it can be turned up for any smaller fish which like a bit of movement.

    A mounting bracket makes it simple to install and fit, as well as to remove when the time is needed. The airline tubing included is safe for both saltwater and freshwater environments, and it is resistant to kinking so will always maintain a continuous flow.

    We have to admit that it isn’t the best at doing the overall job, being better at removing dirt than cleaning the water, so you could still need something else depending on your precise tank setup.

    Features

    • Low level of disturbance
    • Fits all shapes of tank

    Specifications

    • Type: Internal
    • Filter Types: Mechanical
    • Tank Size: Up to 19L
    • Water Flow Rate: 40 LPH

    9.
    Hagen Elite Stingray 10 Underwater Aquarium Filter

    Thanks to the zeo-carb and foam filter media inserts, this filter can deal with chemical, mechanical and biological filtration, despite looking like it wouldn’t do much at all.

    The design is pretty futuristic, which makes a change from the tubular and cubic filters out there. In fact, the ‘Stingray’ name is clearly apt.

    It takes a bit of maintenance, with a need to pull out the impeller (fan) and clean the attached magnet every so often, as well as the fan, so it remains low in noise. The water flow is also quite powerful with no way to adjust, which could be problematic for weaker swimmers.

    Features

    • Small size
    • Quirky design

    Specifications

    • Type: Internal
    • Filter Types: Triple
    • Tank Size: Up to 50L
    • Water Flow Rate: 220 LPH

    10.
    All Pond Solutions 250-CIF Corner Internal Fish Tank Filter

    Fish tank filters aren’t the easiest items to fit if you don’t want it to be highly on show or want to take up as little room as possible.

    So this corner fish filter, which can safely fit into the very corner of your tank (hence the name), will appeal to anyone who wants a sleek look but still needs something powerful.

    The flow rate controller will come in handy if you have fish which don’t like too much movement, and it sits on the top of the unit so can be adjusted at any time. The spray bar cleaner feature offers smooth water filling, spread over an area so it isn’t too intense, as well as a supply of oxygen.

    Two larger sizes are also available, the 450 and 650, for tanks up to 110L. Filter sponges will remove any physical particles from the water, and you get some secure suction cups for securing it to the tank.

    Be aware that there are quite a few holes, so if you have something small such as loach fish, they could get stuck so opt for something else. It is also quite loud.

    Features

    • Corner design

    Specifications

    • Type: Internal
    • Filter Types: Triple
    • Tank Size: Up to 45L
    • Water Flow Rate: 220 LPH

    Buying Guide

    Filtration Types

    There are three broad functions of a fish tank filter – biological, mechanical and chemical.

    Many people may focus on the first issue and be unaware of the others, as it is the only visible form, but the other two are vital in keeping your fish alive.

    There are filters available which focus on just one or two issues, and some which will cope with Triple issues. You should ensure all three bases are covered.

    Biological

    Fish produce ammonia with their gills as they breathe, which is biological waste. They also produce dirt from bodily functions just like any other animal. Despite being naturally occurring, this ammonia is actually quite toxic to fish, especially if left for a while. Even low levels can cause issues such as eye, kidney and liver problems. Filters turn ammonia into nitrate which is less harmful but will still need to be removed with water changes to avoid algae growth

    Mechanical

    You may need a mechanical filter to remove particles such as uneaten food, dust and general dirt from the water. Debris can make the water cloudy, and cause issues such as mould so need to be cleared regularly. This will need to be removed via a media such as a sponge or pad which captures the particulate

    Chemical

    Water can also contain impurities such as hard metals or minerals, and while you should try to get this to the perfect pH level before filling the tank, it needs to be maintained. Activated carbon filters will be needed to stay on top of this

    Types Of Fish Aquarium Filter

    Tank filters can come in very forms, usually separated by where they are situated when in use. But some forms are better at certain filtration types than others, and others are only good for one type of water.

    Internal

    Also known as box filters or corner filters. These can be some of the smallest filters around, good for micro tanks under 20 gallons with maybe just one or two fish in, but can also cope with tanks over 100L. They are also relatively inexpensive.

    Most can be loaded with multiple forms of filter media, so will clear all three filter needs but others may be restricted to one or two, meaning you need an extra filter. Suction cups keep them fastened, and you may also need a pump to help with water flow movement if the suction is weak

    External/Canister

    These look similar to an internal model, except the filter sits on the outside of the tank because of its size. These filters can cope with larger capacities, often over 40 gallons. They draw water in via a siphon method and commonly have three filter sections which can usually deal with all three filtration needs. Some may be poor at biological filtering as they technically don’t use air or gravity to actually move the water and collect it all, so an extra pump could be a good idea too

    Hang On Back/Power

    HoB filters are very popular because they literally hang over your tank, so are simple to fit with no extra tubing. This means they don’t take up space either inside or out and are always easy to access. Most can deal with all three filtration types, cleaning the water before releasing it back into the tank, although they excel with mechanical filtering in particular

    Under Gravel

    As you’d imagine, these are grates which rest under the base level of gravel in your tank. They draw water through the holes on the top and often focus on just mechanical filtration as they collect the debris which falls. Water is then pushed out through the airlift tubes.

    There is no filter to change, making them very cheap and easy to run. Some do have a carbon filter but the effectiveness is limited and they are often just removed, so under gravel filters are not meant to maintain the tank by themselves

    Wet/Dry

    AKA a trickle filter, sump or shower filter. They get their name from the fact that part is exposed to the tank water, and also to a large amount of air.

    Water is siphoned into the internal part and then back out and passed over a biological material source contained in the filter chamber. Bio Balls are the most popular material. This makes them great for biological filtration as they have good access to oxygen, but a bit poorer for the other forms.

    They are most commonly used in saltwater aquariums as they need more help producing beneficial bacteria, and are best bought from knowledgeable dedicated fish pet stores because they are hard to set up and you need to buy the precise size for your tank

    Price

    This all depends on the type of filter you buy, the size of your tank, as well as the ease of maintaining it. You can buy a basic internal filter for as little as £10, and wet/dry or external options can reach closer to £100.

    Be aware that you may find those which are a bit more expensive are better at the overall job, and easier to clean and maintain.

    Other Buyers Ask...

    Why Do I Need A Fish Tank Filter?

    A fish tank filter creates a home for natural bacteria, which helps to lower and remove toxic fish waste.

    Your fish naturally release waste as they breathe and eat, but if the levels get too high as this breaks down, they will poison themselves. This is ammonia stress, which turns into ammonia poisoning when it proves fatal.

    Debris in the water makes it cloudy, which doesn’t just look unpleasant but can also cause health issues for your fish.

    How Do I Choose The Best Filter?

    There are loads of forms of filter, as well as jobs for them to do, so choosing the right one can be a bit of a task. The main things to think about are:

    Tank Size

    Some filters are more adaptable than others. If you know which capacity your tank will be, look for a filter which can cope with these dimensions. Even the smallest of nano tanks should still use some form of filter, as maintenance would be extreme otherwise. There are filters out there especially for small tanks, and HoB filters are often best as they will not take up any internal space

    Water Type

    Saltwater can need slightly different filters and equipment, as the salt can make it harder for some ordinary filters to cope. Wet/dry filters are often the best at this, but you will need to ensure you get the right balance of air

    Water Flow Rate

    This is how quickly the filter can refill the tank. You want the highest number possible here, especially if your tank is large. It is measured in gallons per hour, and you should move the entire tank volume in water through your filter at least twice an hour. This is the best way for all your water to be exposed to the filter in enough time

    However, do make a note of how well your fish can swim. A flow rate which is too high can cause quite a bit of disturbance in the tank, and if you have smaller fish who are weak swimmers, this could be stressful. Opt for a filter with an adjustable flow

    Filter Ability

    You need to cover all three types for a fully clean tank, so if you buy a small under-gravel filter for biological waste, ensure the second filter is best at chemical and mechanical

    Filter Biological Material

    This is the media which captures the physical debris, such as wasted food. It can be a sponge, netting, floss, filter pads or even just air bubbles in saltwater. How coarse this is will depend on how fine the captured particles can be, and some filters are limited as to what you use

    Some filters can also be vital for the production and maintenance of good bacteria which helps them to keep the water clean

    Population

    Got a pretty full tank of fish? They will make more waste than just one fish, so you will need a high performing filter to deal with it

    How Do I Set Up A Filter?

    Internal and HoB filters are the easiest to set up as they can be installed once everything is running and don’t require you to move everything around. Under gravel filters are a bit harder and should be installed before the tank is filled so nothing is disturbed.

    Canister and wet/dry filters often need the most setting up. They are meant for larger tanks, so they have to work harder to do their job and need to be done perfectly.

    How exactly the filters are set up will depend on the particular brand and form, but there will always be instructions and guides to help.

    Which Brands Should I Look Out For?

    Names such as Fluval, Tetra Bio Filter and Penn Pax crop up time and time again when looking for the best fish tank filters.

    What Else Do I Need In My Tank?

    Plants are a great natural, biological filter (although shouldn’t be used on their own). They also encourage the production of the good bacteria which removes a good chunk of the natural pollutants, which filters may remove.

    Some people would argue that plants alone are fine, especially in smaller tanks, but a plant and a filter will give superior results. Filters and pumps also help to move the water about, helping plants take up nutrients more efficiently.

    Don’t put the plants too near the filters though, as this is bad for them.